In vitro gastric and intestinal digestion of a walnut oil body dispersion

J Agric Food Chem. 2013 Jan 16;61(2):410-7. doi: 10.1021/jf303456a. Epub 2013 Jan 3.

Abstract

An oil body dispersion (11.3% fat) was prepared by wet disintegration of walnuts and was then subjected to a two-step model of in vitro digestion. In a gastric environment, proteolysis by pepsin led to the destabilization and coalescence of the oil bodies. Aggregation of the coalesced oil bodies was apparent under a confocal microscope, with aggregates up to 275 μm in size. Pepsin-resistant peptides and proteins remained at the surface of the oil bodies, and some were further resistant to intestinal proteases. Under intestinal conditions, the hydrolysis of walnut triglycerides led to the spontaneous formation of a new type of multiple emulsions, ranging from 2 to 45 μm in size and with protein material inside the inner water droplets. Transmission electron microscopy revealed the presence of a liquid-crystalline phase of bile salts and lipolytic products at the surface of the oil droplets and some bile salt crystals at the surface of the inner water droplets.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Dietary Supplements*
  • Digestion*
  • Emulsions
  • Gastric Juice / enzymology
  • Gastric Juice / metabolism
  • Humans
  • Intestinal Secretions / enzymology
  • Intestinal Secretions / metabolism
  • Juglans / chemistry*
  • Lipolysis
  • Liposomes
  • Nuts / chemistry*
  • Pancreatic Juice / enzymology
  • Pancreatic Juice / metabolism
  • Plant Oils / chemistry
  • Plant Oils / metabolism*
  • Plant Proteins / chemistry
  • Plant Proteins / metabolism*
  • Proteolysis
  • Triglycerides / chemistry
  • Triglycerides / metabolism*

Substances

  • Emulsions
  • Liposomes
  • Plant Oils
  • Plant Proteins
  • Triglycerides